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Stock-Based Compensation (Employee Stock Purchase Plan) (Details) - Employee Stock Purchase Plan - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation expense $ 921 $ 841 $ 750
Common stock shares purchased by Company employees (in shares) 356 254 216
Average purchase price per share (in USD per share) $ 8.33 $ 10.26 $ 11.48